FIELD OF THE INVENTION
The invention relates to a storage basket having a plurality of inserts for receiving a fuel element of a nuclear power plant. The invention also relates to a fuel element storage rack for the compact storage of fuel elements, including a carrying structure for carrying the fuel elements and a storage basket having a plurality of inserts for receiving a fuel element. The invention furthermore relates to a method for the storage of fuel elements and control rods of a nuclear power plant.
In nuclear power plants for generating electrical energy from fissionable material, the fissionable material is inserted in so-called fuel elements. While the nuclear power plant is operating, the fissionable material in the fuel elements is split as a result of a nuclear chain reaction. After the fissionable material has been largely consumed, that is to say spent, the spent fuel elements are intermediately stored in so-called water-filled storage basins. Fuel element storage racks are provided for receiving the fuel elements in the storage basins.
German Published, Non-Prosecuted Patent Application DE 41 34 246 A1 describes a storage rack for fuel elements of a nuclear power plant, in which a plurality of wells having an essentially rectangular cross section are fastened on a base plate. The wells stand upright on the base plate and in each case are disposed diagonally opposite one another in a checkered manner. Some of the wells located diagonally opposite one another are connected to one another along mutually contiguous longitudinal edges through the use of at least two connecting elements. A first connecting element has high rigidity in a first direction which runs parallel to the base plate. A second connecting element likewise has high rigidity in a second direction which likewise runs parallel to the base plate. An angle between the first direction and the second direction is between 70.degree. and 90.degree.. The wells are connected to one another through the connecting elements in a mechanically stable manner, with high carrying capacity, in such a way as to form a unit. The walls of the wells serve as an absorption device for neutron radiation and are composed of an austenitic boron steel with a boron content of up to 2%. The fuel element storage rack described in German Published, Non-Prosecuted Patent Application DE 41 34 246 A1 allows a compact storage of fuel elements, wherein a fuel element is capable of being stored both in each well and in cavities formed between the wells. The fuel elements and the wells are extended along a main axis in each case, with the main axes running essentially parallel to one another. In that case, the main axes are essentially perpendicular on the base plate of the storage rack.
U.S. Pat. No. 4,960,560 describes a storage rack for fuel elements of a boiling water nuclear power plant. The storage rack has a rectangular base plate which rests on feet. A multiplicity of wells, each for receiving a fuel element, is disposed on the base plate. The wells are extended along a main axis which is perpendicular on the base plate. The wells are disposed on the base plate in a checkered manner, with the wells being welded to one another over their entire height along the outer edge of the base plate through the use of metal sheets, so that a continuous closed outer wall is formed. Circular orifices are present in the bottom of the base plate in each well. Moreover, some of the orifices have depressions differing from the circular shape, so that a lifting appliance which is introduced through them, after it has been rotated by a few degrees, can no longer be led through the orifice. As a result, an anchorage of the lifting appliance is provided, in a similar way to the lid of a teapot, and the possibility of lifting the base plate is thereby afforded.
Both German Published, Non-Prosecuted Patent Application DE 41 34 246 A1 and U.S. Pat. No. 4,960,560 relate merely to the compact storage of fuel elements. Neither of the two publications deals with the problem of storing other spent or irradiated core components, in particular control elements and control rods of a boiling water nuclear power plant.